1. Field
This invention relates generally to internal combustion engines and is specifically directed to a two cycle, internal combustion engine. More particularly, this invention is directed towards a means for pressurizing the fuel charge's introduction into the combustion chamber of the engine. The compressing is done internally in the crankcase without adding, additional weight, parts, or power drive devices.
2. Prior Art
Two cycle engines are well known in the art. These engines find application in vehicles such as motorcycles, snowmobiles, or small motorized machinery such as lawnmowers. In general, these engines are used in applications wherein a small weight motor with a large power output is a requirement.
A typical engine construction includes a engine block defining a open-ended cylinder. This cylinder is fitted on its one end with an end cover mounted with a spark plug or a similar ignition type device. Fitted within the cylinder is a piston which is dimensioned and configured to be reciprocally displaced within the cylinder between two opposing positions; a first position wherein the head of the piston is positioned substantially contiguous the cover fitted end of the cylinder, and its attendant spark plug and a second position wherein the piston is positioned proximate the open end of the cylinder.
The piston is fitted with a pivotally mounted connecting rod which extends from the piston to a pivot mounting on a crankshaft. The crankshaft is rotatably mounted within the engine block. In a conventional construction the crankshaft includes an axis of rotation which is oriented substantially perpendicular to the axis of the reciprocating displacement of the piston.
The crankshaft, is mounted in part within a hollow cavity within the engine block generally denoted as a crankcase. The crankcase communicates with a carburetor which is adapted to receive air from the environment and combine that air with a combustible such as gasoline, thereby producing a combustible mixture. The combustible mixture is channeled from the carburetor, through the crankcase and then into a combustion chamber during the engine's operation. The combustion chamber is defined as that space bounded by the cylinder walls, the end cover and the top of the piston.
Since the cylinder is in open communication with the crankcase, a displacement of that piston effects the air pressure within that crankcase. As the piston descends from its uppermost position, i.e. its positioning proximate the cover fitted end, the downward displacement of the piston operates to compress or pressurize the combustible mixture which has been received within the crankcase via the carburetor. When the piston reaches a predetermined location within the cylinder, ports are opened or exposed within the walls of the cylinder. The ports communicate with the combustion chamber. Each of the ports are fed by a respective transfer channel defined within the structure of the engine block. The channels in turn communicate with the crankcase.
The fuel mixture which was pressurized within the crankcase by the downward descent of the piston is directed through the channels into the combustion chamber due to the differential in pressures between the crankcase and combustion chamber.
Upon the piston head reaching its lower-most position i.e., the position proximate the open-end of the cylinder, it begins its upward ascend within the cylinder. As the piston ascends, the air pressure within the crankcase is decreased. As the piston reaches a predetermined height within the cylinder, the ports which permit the entry of combustible mixture into the cylinder are closed. The combustible mixture within the combustion chamber is compressed by the continuing upward ascent of the piston. As the piston reaches a predetermined location in its upward ascent, an electrical charge is directed to the spark plug which in turn produces a spark within the combustion chamber. The spark ignites the fuel mixture and produces a explosive reaction. The explosion directs the piston forcefully downward within the cylinder. Thereafter the process is repeated pursuant to the sequence just described.
An exhaust port or ports are defined within the wall of the cylinder. These ports lead from the combustion chamber to an exhaust manifold. As the piston head descends under the force of the explosion, the exhaust ports, which were sealed by the piston in its uppermost positioning are exposed. Exhaust products produced within the combustion chamber are then evacuated from the chamber through the exhaust ports to the exhaust manifold.
In a conventional engine the displacement of the combustible mixture from within the crankcase upward into the combustion chamber in association with the upward ascent of the piston results in a vacuum or low pressure region within the crankcase itself. The differential in internal pressure between the carburetor and the crankcase facilitates an induction of a charge of combustible mixture from the carburetor into the crankcase.
A compression of the combustible mixture prior to the combustion of that mixture operates to increase the power released by that combustion. In the conventional approach the combustible mixture is somewhat pulsedly compressed within the crankcase by the descent of the piston within the cylinder. This compression in the crank case is enhanced by the compression which subsequently occurs within the upper regions of the combustion chamber as the piston ascends; i.e. that compression of the combustible mixture within the ever decreasing volume of the upper reaches of the cylinder.
The concept of super charging or turbo charging an engine is well known. Typically, turbocharging involves compressing or pressurizing the air portion of the combustible mixture prior to mixing that air with the fuel in the carburetor to form the combustible mixture. This compression is usually accomplished in a structurally separate chamber which is mounted to the exterior of the engine. After being pressurized the air is channeled to the carburetor for purposes of mixing it with fuel.
Other efforts have been directed toward pressurizing the combustible mixture itself i.e., after the mixing of the air and fuel.
U.S. Pat. No. 4,261,306 (Gorr) discloses a deflector plate mounted proximate the periphery of the flywheels housed within the crankcase. The deflectors serve to scoop the boundary layer of combustible mixture which is located adjacent the flywheel periphery and deflect it toward the transfer channels. By doing so Gorr claims that the charging of combustible mixture into the combustion chamber is increased due to the force occasioned by the rapidly moving combustible mixture in the crankcase.
In U.S. Pat. No. 4,362,132 (Newman), a flywheel of the crankshaft is configured to include a periphery annular recess or pocket about approximately 180.degree. of its structure. The pocket is positioned in opposition to the eccentric point of connection of the connecting rod to the flywheel. The pocket cylinder communicates with the fuel inlet port and carburetor. The pocket operates to receive a fuel charge from the carburetor and tangentially throw that charge into the transfer ducts.
U.S. Pat. No. 2,410,471 (Warner) discloses a multi-cylinder radial engine having a crankshaft mounted fan including vanes mounted about half of its perimeter. The Warner fan operates to direct combustible mixture through a channel into a pressure chamber located beneath the reciprocating piston. As the piston descends the combustible mixture is compressed and directed into the combustion chamber of an adjacently positioned cylinder. The solid portion of the blower fan perimeter serves to close the channel. Resultingly, the fan serves as a valve for pulsedly feeding the pressure chamber beneath the piston.